Method of Fitting a Hearing Assistance Device

ABSTRACT

There is provided a method of fitting a hearing assistance device ( 10, 11 ) by using a fitting station ( 40 ), the hearing assistance device and the fitting station both having a wireless communication interface ( 20 ), comprising: generating, separately from the hearing assistance device and the fitting station, a production key, distributing the production key to both the fitting station and the hearing assistance device, and storing the production key on both the fitting station and the hearing assistance device; initiating, via the fitting station, a connection with the hearing assistance device, with the hearing assistance device accepting the connection in order to establish a non-encrypted connection between the fitting station and the hearing assistance device via the wireless communication interfaces; determining, by the fitting station, whether the fitting station has been previously paired with the hearing assistance device, and, if the fitting station has not already been paired with the hearing assistance device, using the production key in both the fitting station and the hearing assistance device as a shared secret in order to pair the fitting station and the hearing assistance device, thereby establishing a secure connection ( 30 ) via the wireless communication interfaces between the fitting station and the hearing assistance device; and conducting a fitting session via a secure connection between the fitting station and the hearing assistance device via the wireless communication interfaces.

The invention relates to a method of fitting a hearing assistancedevice, such as a hearing aid, by using a fitting station, wherein thehearing assistance device and the fitting station communicate via awireless communication interface, such as a Bluetooth interface.

Typically, during a fitting session, a fitting station, which may be aPC or tablet computer on which a specific fitting software is running,is connected to the hearing assistance device via a wirelesscommunication interface in order to adjust the hearing assistance deviceto the individual needs of a user or patient, such as to the individualhearing loss. The wireless interface may utilize a proprietary protocol,or it may use a standard protocol, such as a Bluetooth protocol. Forsafety reasons, it is desirable that the communication between thefitting station and the hearing assistance device is encrypted, i.e. theexchanged data is encoded using a key, and that the fitting station andthe hearing assistance device only communicate with authenticateddevices.

For example, when connecting two devices using Bluetooth technology forthe first time, the two devices to be paired must be brought into apairable mode which requires to perform a pairing gesture, such asentering a PIN, on both devices. However, since an ear level hearingdevice is a relatively small device with a very limited user interface,for example small buttons which are difficult to handle, it is notdesirable to be requested to perform a fitting gesture on the hearingassistance device for pairing with the fitting station.

On the other hand, allowing the hearing device to be continuously andpromiscuously pairable would pose a significant security risk in thatany Bluetooth device could pair with the hearing assistance device, beit at the hearing care provider's office or at a bus station; forexample, by pairing a smartphone with the hearing assistance device inorder to control the patient's hearing assistance devices withoutauthorization.

US 2011/0221590 A1 relates to a method for automatically adding a firstsensor device disposed on a patient's body to a personal area network ina healthcare application, wherein the network is based on Bluetoothcommunication, with out-of-band pairing data being injected into thepatient's body by a second sensor device disposed on the patient's body;pairing data extracted from the signal received at the first sensordevice is used to add the first sensor device to the network.

WO 2014/154151 A1 relates to an out-of-band pairing process of twoBluetooth devices, wherein an audio channel is used as an out-of-bandmedium for exchanging Bluetooth pairing information.

WO 2014/158365 A1 relates to a method for pairing a first and a seconddevice, wherein a third device acting as a pairing apparatus is used toobtain the address of the second device in order to provide it to thefirst device, and wherein the third device initiates removal of an inputand output capability in at least one of the first and second device inorder to force a particular pairing mode.

GB 2512502 A relates to a method for authentication of a new device to amesh network based on the Bluetooth Low Energy protocol, wherein a firstmessage containing an identifier for a new device as well as anauthorization code is received by a second device by analyzing an image,such as a QR code, and wherein the new device sends a second message tothe second device allowing the second device to authenticate the newdevice by comparing the authorization code with the processedinformation sent by the new device.

WO 2003/056746 A1 relates to a method of mutual pairing of a pluralityof Bluetooth devices by transmitting a link key obtained by pairing of afirst device with a second device from the second device to a thirddevice for enabling automatic pairing of the first device with the thirddevice; thus, the link key may be used as a common group key by alldevices of the group for establishing a secure connection without theneed for manual pairing.

U.S. Pat. No. 8,555,063 B2 relates to a method for establishing awireless link key between a remote device and a group device, wherein agroup identifier is transmitted which is then used by the recipientdevice to determine whether the sender device is a member of the sametrusted group and to establish a secure link or pair with the senderdevice, depending on the result of the determination.

It is an object of the invention to provide for a method of fitting ahearing assistance device by a fitting station, wherein a securewireless communication link can be established without the need formanipulation of the hearing assistance device.

According to the invention, this object is achieved by a fitting methodas defined in claim 1.

The invention is beneficial in that by using a production key which isdistributed out-of-band both to the fitting station and the hearingassistance device and by using the production key in both the fittingstation and the hearing assistance device as a shared secret in order topair the fitting station and the hearing assistance device, a so called“secure connection” can be established between the fitting station andthe hearing assistance device without the need for performing a pairinggesture on the hearing assistance device. A “secure connection” as usedhereinafter is a connection over which data is exchanged that isencrypted using a shared key or wherein a shared key is used toauthenticate (typically non-encrypted) data exchanged via theconnection, i.e. the receiver of a message can verify that the messagewas sent by an authorized party.

Preferably, the production key is implemented in the hearing assistancedevice already upon manufacturing of the hearing assistance device.

Preferably, the wireless communication interfaces are adapted to use aBluetooth protocol, such as Bluetooth Low Energy.

According to one embodiment, the fitting station requests, for pairingthe fitting station and the hearing assistance device, the Bluetooth“Secure Simple Pairing” mechanism with “Passkey Entry” associationmodel, wherein the production key is used as the passkey by both thefitting station and the hearing assistance device. According to analternative embodiment, the “Secure Connections” mechanism of Bluetoothversion 4.2 may be used for pairing the fitting station and the hearingassistance device.

According to an alternative embodiment, the fitting station and thehearing assistance device mutually authenticate each other by using theproduction key, wherein, after mutual authentication, the fittingstation requests Bluetooth “Just Works” pairing with the hearingassistance device in order to pair the fitting station with the hearingassistance device.

Preferably, after pairing a new user key is generated by action of atleast one of the fitting station and the hearing assistance device,after which this new user key is distributed to both the fitting stationand the hearing assistance device via the link secured using theproduction key. The new user key is then used as a new long-term key forestablishing a secure connection during the fitting session. In otherwords, the production key is only used for establishing a secureconnection for exchanging a new user key which then is used as along-term key for securing subsequent communication between the fittingstation and the hearing assistance device during the fitting session.

Typically, the hearing assistance device is an ear level device, such asa hearing aid, a cochlea implant device or a wireless headphone. Hearingassistance devices include so called “personal sound amplificationdevices” (PSAPs) as well.

Further preferred embodiments are defined in the dependent claims.

Hereinafter, examples with the invention will be illustrated byreference to the attached drawings, wherein:

FIG. 1 is a schematic representation of a first example of a system forfitting a hearing assistance device;

FIG. 2 is an example of a schematic block diagram of components of thesystem of FIG. 1;

FIGS. 3A to 3C are schematic illustrations of an example of a pairingprocess between a fitting station and a hearing assistance device, withsubsequent pairing of the fitting station with another hearingassistance device and subsequent pairing of the two hearing assistancedevices;

FIG. 4 is an illustration like FIG. 1, wherein the system comprises twofitting stations;

FIG. 5 is a schematic illustration of a variant of the example of FIG.4;

FIG. 6 is a flow diagram of an example of pairing processes of thesystem of FIG. 5; and

FIG. 7 is a flow diagram of another example of a pairing processeswhich, however, does not form part of the invention.

FIG. 1 is a schematic illustration of an example of a system forconducting a fitting method according to the invention, comprising afitting station 40 and a hearing assistance device 10 which may connectwith each other via a Bluetooth link 30. The fitting station 40typically is a computer device, such as a PC or a tablet computer, onwhich a specific fitting software is run and which is connected via anetwork 18 with an office management system which includes a patientdatabase 22. The system further comprises a production facility 24 whichserves to produce and pre-configure the fitting software running on thefitting station 40 and the hearing assistance device 10. The fittingstation 40 is able to communicate with the hearing device 10 via aBluetooth link 30 for conducting a fitting session in order toindividually adjust the hearing assistance device 10 to the individualpreferences and needs of the user of the hearing assistance device 10.Such fitting session may include feedback from the user while wearingthe hearing assistance device 10.

An example of a block diagram of the fitting station 40 and the hearingassistance device 10 is shown in FIG. 2.

In the example of FIG. 2, the hearing assistance device 10 is a hearingaid comprising a microphone arrangement 12 for capturing audio signalsfrom ambient sound, an audio signal processing unit 14 for processingthe captured audio signals and an electro-acoustic output transducer(loudspeaker) 16 for stimulation the user's hearing according to theprocessed audio signals.

The hearing aid 10 also comprises a wireless interface 20 comprising anantenna 26 and a transceiver 28.

The interface 20 is provided for enabling wireless data exchange betweenthe first hearing aid 10 and other devices, such as a second hearing aidof a binaural system, an audio streaming device, or a remote microphone,via a wireless link.

The interface 20 is also provided for data exchange via a wireless link30 with a fitting station comprising a wireless interface 20.

For example, the interface 20 may be adapted to operate in a frequencyrange of 0.38 GHz to 5.825 GHz, preferably at frequencies around 2.4 GHzin the ISM band. Typically, the interface 20 is a Bluetooth interface;alternatively, it may use another standard protocol or proprietaryprotocol.

The hearing aid 10 also comprise a controller 38 for controllingoperation of the hearing aid 10, with the controller 38 acting on thesignal processing unit 14 and the transceiver 28, and a memory 36 forstoring data required for operation of the hearing aid 10 and datarequired for operation of the interface 20, such as pairing/networkdata.

The first hearing assistance device typically is an ear level device andpreferably forms part of a binaural hearing system. For example, thehearing assistance device may be a hearing aid, such as a BTE (behindthe ear), ITE (in the ear) or CIC (completely in the channel) hearingaid, or an auditory prosthesis, such as a cochlear implant.Alternatively, the hearing assistance device may be a wireless headphonewhich requires or enables fitting in the sense of individual adjustment.

Before a fitting session with the hearing assistance device 10 can beperformed, it is necessary to pair the fitting station 40 with thehearing assistance device 10. In order to minimize the manualinteraction required for the pairing procedure, while neverthelessproviding for a secure communication link and avoiding promiscuouspairing of the hearing assistance device 10, both the fitting station 40and the hearing assistance device 10 are provided with the sameproduction key prior to any pairing action, where the production key isused as a shared secret for pairing the fitting station 40 and thehearing assistance device 10. For example, the hearing assistance devicecould be configured to only pair with a device with the right productionkey, and only when the hearing assistance device is fresh out of thebox. Alternatively, gesture-less pairing may work only for devices withthe right production key, but for others, pairing may be allowed bygesture. Another example is to allow multiple production keys and allowgesture-less pairing with any device that knows one of the productionkeys.

The production key typically is generated at the production facility 24,i.e. separately from the hearing assistance device 10 and the fittingstation 40, and then is distributed to both the fitting station 40 andthe hearing assistance device 10 for being persistently stored by boththe fitting station 40 and the hearing assistance device 10. Preferably,the production key is provided to the hearing assistance device 10 uponmanufacturing at the production facility 24. The production key may bedistributed to the fitting station 40 as part of a software packagewhich is to be run on the fitting station 40; in this case theproduction key is associated with the fitting software during productionof the software. Alternatively, the production key may be provided tothe fitting station 40 separately from the distribution of the fittingsoftware in order to at least slightly increase the degree of securityin case of pirating of the fitting software; for example, the productionkey may be distributed to the fitting station 40 via a communicationnetwork, such as the internet, or on a data carrier, such as a CD.

Preferably, the same production key may be used for a plurality ofhearing assistance devices of the manufacturer, since in this case thefitting station/fitting software does not have to be provided with (anddoes not have to store) a separate production key for each hearingassistance device. Alternatively, a separate production key may be usedfor each brand of the manufacturer.

When the hearing care professional starts a fitting session with thehearing assistance device 10 for the first time, the production key isavailable as a shared secret both in the fitting session 40 and thehearing assistance device 10. For starting the fitting session, thefitting software is started on the fitting station 40 and a new fittingsession is created for the patient using the hearing assistance device10. The hearing care provider then directs the fitting station 40 toconnect to the hearing assistance device 10, for example by pressing a“connect” button in the fitting software, whereupon the fitting softwaresearches for hearing devices within range and presents them to thehearing care provider for selection (the fitting station 40, togetherwith the fitting software, provides for an appropriate graphical userinterface). The hearing care provider then selects the desired hearingassistance device 10, whereupon the fitting software initiates aconnection with the hearing assistance device 10.

The search for hearing assistance devices within a range of the fittingstation 40 may be performed by the fitting software as a regularBluetooth device discovery as specified in the Bluetooth standard,wherein a filter may be applied to present only hearing assistancedevices of a desired brand, e.g. by applying a filter based on the MACaddress of the hearing assistance device 10.

In order to initiate a connection to the hearing assistance device 10,the fitting software creates an unsecure, i.e. open/non-key protected,Bluetooth connection to the selected hearing assistance device 10, withthe hearing assistance device accepting the connection. The fittingsoftware then determines, for example by a look-up in the patientdatabase 22 of the office management system, whether the fitting station40 already has been paired with the hearing assistance device 10 or not.If the fitting software and the hearing assistance device 10 determinethat the fitting station 40 has not already previously been paired withthe hearing assistance device 10, the production key is used in both thefitting station 40 and the hearing assistance device as a shared secretin order to pair the fitting station 40 and the hearing assistancedevice 10, whereby a secure connection is established between thefitting station 40 and the hearing assistance device 10. Once suchsecure Bluetooth connection has been established, a fitting session maybe conducted using the secure connection.

According to one embodiment, the fitting software, for achieving pairingwith the hearing assistance device 10, requests the Bluetooth “SecureSimple Pairing” mechanism with “Passkey Entry” association model,wherein the production key is used by the fitting software and thehearing assistance device 10 as the passkey in the Passkey Entryassociation model. More in detail, the fitting software first uses theproduction key as input to the pairing algorithm of the Secure SimplePairing” mechanism, and the hearing assistance device 10, due to itsknowledge of the production key, determines that the pairing requestcomes from an authorized fitting software, accepts the request and usesits current user key, namely the production key, as the passkey. Sincethe fitting software and the hearing assistance device 10 thus use thesame key, pairing will succeed and the fitting station 40 and thehearing assistance device 10 are paired. The fitting software nowcreates a secure link with the hearing assistance device 10 usingsecurity information derived during the pairing process, i.e. thecurrent user key, namely the production key, is used as a key forprotecting the link 30.

The fitting software then generates a new user key, which may be arandom key, and transmits the new user key via the link 30 protected bythe production key to the hearing assistance device 10. The hearingassistance device 10 then persistently stores the received new user keyas its current user key, with the new user key then being used as abasis for protecting the link 30 during the fitting session (inpractice, the new user key is used generate a temporary session keywhich the is used as the actual key for protecting the link during thefitting session). Finally, the fitting software persistently stores thenew user key, together with patient data and other hearing assistancedevice data, in the patient database 22 of the office management system.Thus, this new user key is used as a long-term key for the paireddevices.

As an alternative to the generation of the new user key by the fittingsoftware alone, the new user key may be generated by a cooperation ofthe fitting software and the hearing assistance device 10 to prevent thenew user key from being transmitted between the devices or by thehearing assistance device 10 alone (in the latter case, the new user keywould be transmitted from the hearing assistance device 10 via the link30 protected via the production key to the fitting station 40).

According to this pairing procedure, the production key preferably isused only once (according to an alternative—though notpreferred—embodiment the production key can always be used, which allowsfor other fitting stations with the production key to be also pairedwith the hearing device without gesture on the device) as a temporary(“short-term”) key for establishing a secure link which then can be usedto securely distribute a new user key generated by the fitting softwareand/or the hearing assistance device to the respective other device; thenew user key then replaces the production key as the key used forprotecting the link 30 between the fitting station 40 and the hearingassistance device 10, and the new user key is stored both by the hearingassistance device 10 and the fitting station 40 for use in the presentfitting session and in future fitting sessions (as already mentioned,the new user key then serves as a basis for generating a temporarysession key for each fitting session). Thus, in summary, the productionkey serves as input to a process for generating a Bluetooth long-termkey, from which the respective temporary session key is derived.

In other words, the new user key may be used to bond the fitting station40 and the hearing assistance device 10, so that the pairing proceduredoes not have to be repeated in future fitting sessions. By using theproduction key only for the very first pairing of the hearing assistancedevice 10 and the fitting station 40, the security of the pairingprocedure is enhanced, since even if the production key is leaked, thesecurity of hearing assistance devices already having been paired willnot be compromised (an external Bluetooth device trying to pair with thehearing assistance device 10 by using the production key would not besuccessful once a hearing assistance device 10 has been paired once withthe fitting station 40).

According to one example, the hearing assistance device 10 may beadapted to be reset to factory settings, so that the production key willbe re-used for future pairing procedures with the fitting station 40 (orother devices provided with the production key), i.e. by resetting thehearing assistance device the current user key is set to the productionkey, rather than to the new user key described above.

Further, the fitting software and the hearing assistance device 10 maybe designed such that if an attempt to reestablish the secure link usingthe new user key fails, the production key is re-used in both thefitting software and the hearing assistance device 10 as a shared secretin order to pair the fitting station 40 and the hearing assistancedevice 10 as described above. This may happen, for example, when thehearing assistance device, which may have limited persistent memory,removes the stored new user key for some reason.

A schematic flow diagram of the pairing procedure described above isshown in FIG. 3A.

Another pairing example is shown in FIG. 3B, wherein a remote microphone15, rather than a hearing assistance device 10, is paired with thefitting station 40.

FIG. 3C shows an example of a pairing process between the remotemicrophone 15 and the hearing aid 10, with both devices 10, 15previously having been paired with the fitting station 40. In case thatthe fitting station 40 has generated the same new user key in thispairing process, the current user key of the hearing aid 10 and theremote microphone 15 is the same, namely it is the new user keygenerated by the fitting station 40. In this case, the devices 10, 15may pair with each other by using the Bluetooth “Simple Secure Pairing”mechanism with the “Passkey Entry” association model, without a need formanual action.

According to an alternative embodiment, the pairing according to the“Secure Simple Pairing” mechanism as described above may be replaced bya “Just Works” pairing after mutual authentication using the productionkey as a shared secret. More in detail, once the fitting software hasdetermined that it has not been paired before with the hearingassistance device 10, the fitting software authenticates the hearingassistance device 10 using the fitting software's current user key,namely the production key (“authentication” means that the fittingsoftware digitally signs a message using the key and sends the messagealong with the signature to the other device, which then performs thesame procedure and finally compares the locally generated signature withthe received signature). If authentication of the hearing assistancedevice 10 fails, the fitting software aborts the pairing procedure. Ifauthentication is successful, the hearing assistance device 10 thenauthenticates the fitting software using the current user key of thehearing assistance device 10, namely the production key. Ifauthentication of the fitting software fails, the hearing assistancedevice 10 aborts the pairing procedure. Once mutual authentication ofthe two devices 10, 40 is successful, the fitting software requestsBluetooth “Just Works” pairing with the hearing assistance device 10;due to the mutual authentication, the two devices trust each other toperform a “Just Works” pairing (and would not accept a “Just Works”pairing with any other device), so that the “Just Works” pairingsucceeds and the fitting software and the hearing assistance device 10are paired.

The further procedure is like in the “Secure Simple Pairing” exampledescribed above, i.e. the secure link established by using theproduction key is used for securely exchanging a new user key which thenis used as a basis for the session key protecting the link during thefitting session.

In FIG. 4 a variant of the example shown in FIG. 1 is illustrated,wherein the hearing assistance device 10 may communicate with severalfitting stations, with a second fitting station being indicated in FIG.4 at 41. Such situation may occur in larger offices of a hearing careprovider or with a hearing care provider running several offices. Thefitting stations 40, 41 are connected to the same office managementsystem (database 22) via the network connection 18. A typical situationfor such systems comprising a plurality of fitting stations 40, 41 isthat the first fitting session is performed via a first fitting station40, and a later second fitting session is performed via a second fittingstation 41 in the same office or in a different office, with the samehearing assistance device 10 being involved.

According to one embodiment, the new user key generated during the firstpairing process of the first fitting station 40 with the hearingassistance device 10 is stored in the patient database 22 maintained bythe office management system, as already mentioned above. The secondfitting station 41, when pairing with the hearing assistance device 10for performing a subsequent fitting session, may retrieve the new userkey from the database 22, so that it may pair with the hearingassistance device 10 without need for further manual action of thehearing care provider once the hearing assistance device 10 has beenselected as the desired device on the second fitting station 41. In thiscase, the new user key generated during the first pairing of the hearingassistance device 10 with the first fitting station 40 would be used assome kind of “group user key” which may be used by several fittingstations. Such use of a group user key would provide for a particularlyfast connection setup for fitting sessions utilizing a second fittingstation.

However, it also may be preferable, for the reasons explained below, touse only non-persistent storage of pairing information in the connectionbetween the hearing assistance device 10 and the respective fittingstation via the Bluetooth link 30. In such case, the new user keygenerated during the pairing procedure is not permanently stored by thehearing assistance device 10 and the fitting station, i.e. the new userkey is used as a basis for the session key only during present fittingsession, but it is not available for the next fitting session, so thatfor each fitting session the entire pairing process, including use ofthe production key as a shared secret for establishing a secure linkwhich may be used for exchanging the new user key, has to be repeated(as already mentioned above, the production key and the (new) user keyserve to authenticate the devices and to generate a pairing key, whichpairing key is then used to create a session key, which is the actualkey used to encrypt/secure the link during a fitting session). This maycause a delay compared to the case in which a persistently paired (i.e.bonded) pair consisting of a certain fitting station and a certainhearing assistance device is connected.

One reason for not storing the new user key persistently may be thetypically limited persistent memory of hearing assistance devices.Further, the situation concerning the persistent storage of pairinginformation may be even more precarious for the fitting station/fittingsoftware: while a hearing assistance device may only pair with a fewfitting stations, a fitting station is likely to pair with hundreds ofhearing assistance devices, which pairing information may “pollute” thefitting station's memory and cause performance bottlenecks;consequently, non-persistent pairing may be beneficial for the fittingstation as well.

In this case, the production key is stored persistently in the patientdatabase, but the actual pairing key is only temporarily stored in thefitting station memory for the duration of the fitting session.

As already mentioned above, the new user key generated during the firstpairing procedure may be unique for each hearing assistance device.

FIG. 5 is a schematic illustration of a system comprising a plurality offitting stations, similar to the system of FIG. 4, wherein the same newuser key is used by each of the associated fitting stations whencommunicating with the same one (e.g. a first one) of a plurality ofhearing assistance devices 10, 11 to be used by the same user 13; whencommunicating with another one (e.g. a second one) of the hearingassistance devices 10, 11, each of the associated fitting stations usesthe same new user key (pairing key), which, however, may be differentfrom the new user key used for communication with the first one of thehearing assistance devices (in other words, a first key X may be used bythe fitting stations for communicating with the first hearing assistancedevice, and a second key Y may be used by the fitting stations forcommunicating with the second hearing assistance device). In the exampleof FIG. 5, the first hearing aid 10 may be paired with the first fittingstation 40 in the manner described with regard to FIG. 4, i.e. pairingdata including the new user key is generated and stored by the firstfitting station 40 and the first hearing aid 10. This new user key (or,more precisely, a session key derived from the new user key) is used forestablishing a secure link 30 between the first fitting station 40 andthe first hearing aid 10 for performing a fitting session. Such pairingdata also includes device IDs. Further, the first fitting station maygenerate an identity tag and may associate the identity tag with thepairing data; the identity tag and the pairing data may be stored bothby the first hearing aid 10 and the first fitting station 40.

This pairing procedure similarly applies to the second hearing aid 11,wherein, the new user key generated during pairing of the second hearingaid 11 with the fitting station 40 may be different from new user keygenerated during pairing of the first hearing aid 10 with the fittingstation 40; according to an alternative embodiment, the same new userkey may be used also for the second hearing aid 11.

The identity tag and the pairing data then may be transferred to thesecond fitting station 41 for being used (as a basis for deriving asession key) in a later fitting session wherein the second fittingstation 41 is automatically paired with the first and second hearing aid10, 11 based on the identity tag and the associated pairing datareceived from the first fitting station 40, so that the new user key (ornew user keys) generated at the beginning of the first fitting sessionis (are) used for establishing a secure link 30 between the secondfitting station 41 and the hearing aid 10, 11 in a later fitting session(namely as a basis for the deriving a session key).

According to one embodiment, the identity tag may be a static randomBluetooth address used by the first fitting station 40 at the time ofthe pairing with the first hearing aid 10, wherein the second fittingstation 41 adopts the identity tag as its Bluetooth address.

According to another embodiment, the second fitting station 41communicates the identity tag to the hearing aids 10, 11, wherein thehearing aids 10, 11 and the second fitting station 41 retrieve thepairing data associated with the identity tag. In the first embodiment,the hearing aid 10, 11 will not be able to distinguish the secondfitting station 41 from the first fitting station 40 and will be able tocommunicate with the second fitting station 41 in the same manner aswith the first fitting station 40. In the second embodiment, the hearingaid 10, 11 will be able to associate the pairing information obtainedfrom the initial pairing with the first fitting station 40 and, as aresult, will be enabled to communicate with the second fitting station41 via a secure link.

In all embodiments, the Bluetooth technology to be used may be BluetoothLow Energy. When using a static random address according to theBluetooth Low Energy specification, the Bluetooth stack may be resetprior to the assignment of a new random address.

The fitting stations may be assigned a new random address every timepairing with hearing assistance devices associated with a differentpatient 13 is performed.

An example of a flowchart of the first embodiment, wherein a staticrandom address is used as the identity tag, is illustrated in FIG. 6,and an example of a flow diagram of the second embodiment, wherein theidentity tag is communicated to the hearing aid, is illustrated in FIG.7.

Preferably, the identity tag and the pairing data is transferred fromthe first fitting station 40 to the second fitting station 41 via adatabase 22 of the office management system, i.e. the identity tag andthe pairing data is stored by the first fitting station 40 in thedatabase 22 and the second fitting station 41 is connected to thedatabase in order to retrieve the identity tag and the pairing data fromthe database. Such database 22 may be implemented on a single,stand-alone memory device, or it may be implemented as a clouddistributed on a plurality of memory devices.

Alternatively, a network connection may be established between the firstfitting station 40 and the second fitting station 41, and the identitytag and the pairing data may be transmitted from the first fittingstation 40 to the second fitting station 41 via the network connection(rather than storing it on a central database).

According to another embodiment, a portable storage device may be usedfor transferring the identity tag and the pairing data; in this case,the first fitting station 40 would be connected to said portable storagedevice in order to transfer the data to the portable storage device,then the portable storage device will be moved to the second fittingstation 41 and connected to the second fitting station 41 in order totransfer the data from the portable storage device to the second fittingstation 41.

According to one example, which is not part of the present invention,the first pairing process, i.e. the first pairing between the firstfitting station 40 and the first hearing aid 10 may be a conventionalBluetooth pairing process, without using a pre-stored production key inthe first fitting station 40 and the first hearing aid 10; suchconventional Bluetooth pairing process may require interaction of thehearing care provider with the first fitting station 40 or the firstfitting station 40 and the first hearing aid 10.

According to another example, which likewise is not part of the presentinvention, the concept of transferring pairing information obtained bypairing of a hearing assistance device with a first external device,such as a first fitting station, to a second external device, such as asecond fitting station for enabling automatic pairing of the hearingassistance device with the second external device may be applied also tonon-fitting devices. For example, at least one of the external devicesmay be an audio source for providing an audio stream to the hearingassistance device. According to another example, at least one of theexternal devices may be an audio communication device, such as a mobilephone, a landline phone or an internet phone device. According to astill further example, at least one of the external devices may be a TVset, a personal computer, a tablet computer, a radio device or a mediaplayer (in the example of FIG. 7, the first and second external devicesare TV-sets A and B). According to another example, at least one of theexternal devices may be an accessory device of a hearing device, such asa wireless microphone, a remote control or an audio streamer device.

1. A method of fitting a hearing assistance device by using a fittingstation, the hearing assistance device and the fitting station bothhaving a wireless communication interface, comprising: generating,separately from the hearing assistance device and the fitting station, aproduction key; distributing the production key to both the fittingstation and the hearing assistance device, and storing the productionkey on both the fitting station and the hearing assistance device;initiating, via the fitting station, a connection with the hearingassistance device, with the hearing assistance device accepting theconnection to establish a non-encrypted connection between the fittingstation and the hearing assistance device via the wireless communicationinterfaces; determining, by the fitting station, whether the fittingstation has been previously paired with the hearing assistance device,and using the production key in both the fitting station and the hearingassistance device as a shared secret to pair the fitting station and thehearing assistance device, thereby establishing a secure connection viathe wireless communication interfaces between the fitting station andthe hearing assistance device; and conducting a fitting session via asecure connection between the fitting station and the hearing assistancedevice via the wireless communication interfaces.
 2. The method of claim1, wherein the same production key is used for a plurality of hearingassistance devices.
 3. The method of claim 1, wherein the production keyis generated at the manufacturer of the hearing assistance device, andwherein the production key is stored on the hearing assistance deviceupon manufacturing of the hearing assistance device.
 4. (canceled) 5.(canceled)
 6. The method of claim 1, wherein each wireless communicationinterface is adapted to use a Bluetooth protocol.
 7. (canceled) 8.(canceled)
 9. The method of claim 1, wherein after pairing, a new userkey is generated by action of at least one of the fitting station (40)and the hearing assistance device which is distributed via the secureconnection (30) to both the fitting station and the hearing assistancedevice, and wherein the new user key is used for generating the secureconnection during the fitting session.
 10. The method of claim 9,wherein the new user key is generated by the fitting station and istransmitted via the secure link to the hearing assistance device. 11.The method of claim 9, wherein the new user key is a random key andwherein the new user key is used for deriving a session key which isused for the secure connection during the fitting session. 12.(canceled)
 13. (canceled)
 14. (canceled)
 15. The method of claim 1,wherein the new user key is stored by both the fitting station and thehearing assistance device, and wherein the fitting station and thehearing assistance device retrieve the stored new user key and use itfor generating a secure connection between the fitting station and thehearing assistance device in a subsequent fitting session.
 16. Themethod of claim 1, wherein in case that an attempt to reestablish thesecure connection using the new user key fails the production key isre-used by both the fitting station and the hearing assistance device asa shared secret in order to re-pair the fitting station and the hearingassistance device.
 17. (canceled)
 18. (canceled)
 19. (canceled) 20.(canceled)
 21. (canceled)
 22. (canceled)
 23. (canceled)
 24. A method forconducting a fitting session, the method comprising: generating,separately from a hearing device and a fitting station, a productionkey; distributing the production key to both the fitting station and thehearing device; initiating, via the fitting station, a connection to thehearing device to establish a non-encrypted connection between thefitting station and the hearing device; using the production key in boththe fitting station and the hearing to pair the fitting station and thehearing device to establish a secure connection between the fittingstation and the hearing device; and conducting a fitting session via thesecure connection between the fitting station and the hearing device.25. The method of claim 24, wherein the hearing device is at least oneof following: a hearing aid; a hearing assistance device; behind the earhearing device; in the ear hearing device; a completely in the canalhearing device; or cochlear implant.
 26. The method of claim 24, whereinthe production key is associated with gesture-less pairing for thehearing device.
 27. The method of claim 24, the method furthercomprising: determining, by the fitting station, whether the fittingstation has been previously paired with the hearing device; and based ondetermining the fitting station has not previously paired with thehearing device, automatically establishing the secure connection betweenthe hearing device and the fitting station.
 28. A non-transitorycomputer readable medium storing instructions that when executed by aprocessor cause a fitting station and a hearing device to performoperations, the operations comprising: generating, separately from ahearing device and a fitting station, a production key; distributing theproduction key to both the fitting station and the hearing device, andstoring the production key on both the fitting station and the hearingdevice; initiating, via the fitting station, a connection to the hearingdevice to establish a non-encrypted connection between the fittingstation and the hearing device; using the production key in both thefitting station and the hearing to pair the fitting station and thehearing device to establish a secure connection between the fittingstation and the hearing device; and conducting a fitting session via thesecure connection between the fitting station and the hearing device.29. The non-transitory computer readable medium of claim 28, wherein thehearing device is at least one of following: a hearing aid; a hearingassistance device; behind the ear hearing device; in the ear hearingdevice; a completely in the canal hearing device; or cochlear implant.30. The non-transitory computer readable medium of claim 28, wherein theproduction key is associated with gesture-less pairing for the hearingdevice.
 31. The non-transitory computer readable medium of claim 28,wherein the operations further comprise: determining, by the fittingstation, whether the fitting station has been previously paired with thehearing device; and based on determining the fitting station has notpreviously paired with the hearing device, automatically establishingthe secure connection between the hearing device and the fittingstation.